Gold doesn’t work alone. Au, the chemical symbol for pure gold, is a soft, dense and inert yellow element that is the most malleable and ductile of all metals but requires mixing with other metals to increase its strength.
And to make gold stronger, any number of elements can be combined with it, each creating its own color. Depending on the gold mixed with it, it can appear brilliant white, warm pink or even copper red, and can be made even more resistant to corrosion and tarnish, both qualities long demanded of the metal.
From the late 13th century, gold was used in the tower clocks of churches, monasteries and castles across Europe, with gold leaf used to coat the numerals and hands. Pocket watches, however, offered a new challenge. Gold was regularly used from the first pocket watches soon after 1500, but as they were expensive and not particularly accurate, they were as much adornment as timekeeper.
Girard-Perregaux might have been the first to create an all-gold wristwatch, commissioned by the German Emperor as early as 1879. He asked the company to manufacture corrosion-resistant deck watches for navigating the high seas and, for this reason, the cases were fashioned from 14-karat gold.
Constant Girard-Perregaux, founder of the Girard-Perregaux company, loved gold, his favorite being 18-karat pink gold (with 20.5 percent copper and 4.5 percent silver). He used it for the case, dial, hands, crown and movement parts. Around 1880, he came up with a tourbillon with three gold bridges pocket watch masterpiece in pink gold, now a Girard-Perregaux classic in wristwatch size.
The modern alloying process, undertaken to increase durability and wearability, now combines pure gold with other metals to create a diverse color palette. To create hues commonly found in watch cases, technicians mix white metals, such as palladium or silver, to create white gold, while the inclusion of copper creates rose gold.
In the 18th century, as metallurgists learned to analyze quantitatively, standardized alloys began to appear, with gold alloys used in watchmaking discovered by trial and error. Today, the proportion of gold in watches varies considerably from country to country and is preserved not only by custom but also often by law.
Fourteen-karat cases are made for Britain, Germany and the United States, where gold under ten karats is illegal and cannot be sold as gold. The advantage of lower karatage is that a wider range of color may be attained, depending on the balance of other metals with which it is alloyed. Strength, hardness and therefore wear-and scratch-resistance tend to increase as karatage is lowered. Nonetheless the higher the karatage, the more expensive the result and the greater the status symbol.
Higher-karat golds are made of 87 or 91 per cent gold (21 and 22 karat) and are particularly prevalent in India and the Middle East. Favored by Chinese luxury consumers, 18-karat gold – the karatage at which gold can begin to change color as other metals are added to the alloy – has been adopted as the karatage of choice for the world’s leading watch brands.
Cases made by the Swiss watch industry are almost exclusively in 18-karat gold, which has a good percentage of precious metal content and is easy to work yet has good metallurgical properties. No Swiss manufacturer will ever go to a lower gold alloy than 18-karat; this would be suicidal for its reputation, says Lucien Trueb, author of several books on horology. Aside from that, the top-brand watches must be expensive – they are highly emotional status symbols. Do you cut corners when making a Ferrari? Is it bought because it is cheap?
Dr. Chris Corti, formerly technical expert for the World Gold Council and now technical consultant for the Worshipful Company of Goldsmiths, notes that economics dictates what karatages of gold are used.
Generally, 18-karat gold is preferred for quality watches as it is strong and wear-resistant, while 22- and 24-karat golds are soft. Fourteen and 9- or 10-karat gold is also used in markets where a cheaper (than 18-karat) gold is required and where such alloys are legal and popular, he adds.
Each year, almost 500,000 gold watches are made, ninety per cent of them in Switzerland; the watchcases and bracelets comprise close to thirty tons of gold. Gold watches accounted for more than ninety-four percent of total Swiss watch exports by value in 2012. While standard yellow gold was favored by the watch industry for decades, the past ten years have seen this change, with successively white gold and today red gold being the most popular.
Precinox in La Chaux-de-Fonds in Switzerland, which does its own chemical and electrochemical refining, has more than twenty alloys in the 18-karat class for applications in horology. One of the world’s largest processors of precious metals, Argor-Heraeus is a supplier of karat golds to the watch industry, and precious metals refiner Metalor, based in Neuchâtel, Switzerland, supplies alloys and semi-finished products to the Swiss watch industry.
While gold alloy production is very conservative in the watchmaking world, several larger companies have in recent years begun their own recipes to create specialized alloys that relate to their brand or type of watchmaking.
Rolex is the biggest maker of gold watches by far, producing more than 200,000 gold timepieces annually. An integrated manufacturing company, Rolex designs, develops and produces in-house all the essential components of its watches, from the casting of gold alloys to the machining, crafting, assembly and finishing of the movement, case, dial and bracelet. It creates 18-karat yellow gold, white gold and Everose gold alloys, which are cast in its own foundry before being formed, machined and polished in its workshops.
The exclusive hue of its 18-karat Everose gold (a patented pink gold alloy), for example, is enhanced by a touch of platinum, which locks in the copper and thus the color, found in the Oyster Perpetual Day-Date, Lady-Datejust Pearlmaster, Cosmograph Daytona and Yacht-Master II.
Highlighting the natural crystal structure of gold, Rolex’s Gold Crystals dials are manufactured from a specially developed 18-karat gold alloy. They undergo a particular surface treatment that reveals the many-faceted crystals in the metal, producing dials totally different from one another. First introduced in 2008 for the counters on a Cosmograph Daytona model, Gold Crystals dials have also appeared in certain models of the Lady-Datejust collection since 2011.
Chopard is another company with its own in-house gold foundry. With more than thirty varying crafts involved, it controls the entire range of production processes for its watches and jewelry, from gold-casting to gem-setting the case – like on the Happy Sport watch – to ensure quality and a fast response to its own needs.
Chopard makes five different 18-karat gold alloys from 24-karat yellow gold ingots in its workshop located in its Meyrin headquarters: a white gold shade, two shades of yellow gold (2N and 3N) and two shades of rose gold (4N and 5N). The gold bars obtained by rolling are then subjected to stamping, after which the case blanks are cut out from the raw material and undergo several more machining stages before reaching their final state.
Hublot is replacing traditional gold with high-tech alloys and ceramic composites that are more durable and resist scratches. The aim is not just to make new materials, but also to use new materials to make better products.
Since 2011, Hublot has used the 18-karat King Gold alloy in its timepieces, including the Classic Fusion Chrono Aero King Gold, Big Bang Ferrari King Gold Carbon and MP-06 Senna. The red gold contains five percent platinum, making it an even more precious metal. The intense red color, more red than traditional 5N red gold, is the result of Hublot’s metallurgists having increased the percentage of copper and added platinum to stabilize the color over the years and to neutralize oxidation.
Today, Hublot continues to write the story of the art of fusion by combining unusual materials with more conventional ones. It is producing its signature Big Bang watches like the Big Bang Ferrari Magic Gold using its patented 18-karat Magic Gold, which Hublot says is the world’s first scratch-resistant gold.
Dr. Senad Hasanovic, Head Director of Hublot’s metallurgy department and foundry located in the manufacture in Nyon where watchcases and movements are produced, jointly developed the ceramic-gold composite in 2011 with Professor Andreas Mortensen from the Swiss Federal Institute of Technology Lausanne.
Magic Gold is so hard only a diamond will mark it. Almost three years of collaboration and research went into achieving this impressive result. The pair injected molten liquid gold under high pressure into ceramic causing the two to fuse into a single new material. The gold is produced in the well-equipped Hublot foundry where the firm conducts all its own refractory ceramic sintering and high-pressure metal casting.
The technology used to develop Magic Gold can also be applied to other metals, including silver and platinum, and Hublot has already used the process to make an aluminum alloy.
Our concept to always try to be first, different and unique made us think about a new gold alloy with new properties, says Jean-Claude Biver, Chairman of Hublot. As we have a twenty-year-long patent, it is far better to keep this technology at home rather than to have it made by third parties. Furthermore, any new development should always be developed and experienced at home as we have better feedback and can immediately profit from experiences and adjustments.
In 2012, Panerai devised its own red gold alloy. Called Oro Rosso, Italian for red gold, the metal has been used by the brand for its recent models, including last year’s Luminor Marina 8 Days (PAM00511), Radiomir 1940 (PAM00515) and Luminor 1950 Chrono Flyback (PAM00525).
Composed of 75 per cent gold, 24.1 per cent copper and 0.4 per cent platinum, the red gold is a special alloy named 5Npt, which has an unusually high percentage of copper, giving a solid, elegant red color. Platinum is also added to prevent any oxidation and to stabilize the alloy. The difference between red and pink gold is the higher copper content (24.1 percent), which gives a stronger red coloration when compared to the standard 20.5 percent copper alloys in red gold.
Omega’s involvement in the evolution of gold began in 1960 when it introduced the 18-karat Multi-Color Gold Compression timepiece. This model was a world premiere in terms of watch design and gold compression as it blended shades of 18-karat gold to create a final product that incorporated tints of blue, pink, yellow and white gold.
In 2011, Omega released the Speedmaster Moonwatch OMEGA Co-Axial Chronograph, the first watch to be crafted in 18-karat orange gold, whose elemental composition contributes to its unique hue and high level of hardness.
Like all of the gold used in Omega’s products, orange gold is 18-karat, incorporating a high copper content (23.98 per cent), which contributes to its vivid color. The remaining 1.02 per cent is divided evenly between platinum and silver. The platinum enhances the hardness of the material and the value of the precious metal, and the fact that platinum doesn’t oxidize acts to stabilize the reddish color.
In 2012, Omega unveiled a new Seamaster Planet Ocean using Ceragold, the first product to allow the incrustation of 18-karat gold for numbers and scaling into zirconium-based ceramic bezels, resulting in a smooth blended material.
The following year, Omega introduced Sedna gold, an 18-karat rose gold alloy blending gold, copper and palladium developed 100 percent in-house, used in the Constellation Sedna timepiece.
This was followed by the De Ville Ladymatic Diamonds and Pearls watch dressed in the same rose gold luster, which is particularly long-lasting thanks to its palladium content.
The research, development and production of Omega’s gold alloys take place at Swatch Group sister companies and gold manufacturers in Switzerland with teams of internal metallurgists and engineers.
The timepieces made with orange gold, Ceragold and Sedna gold are truly unique and serve as excellent examples of the kinds of advancements that have helped Omega become one of the world’s leading mechanical watch brands, says Stephen Urquhart, President of Omega. Developing these new materials allows us to bring a modern touch to our iconic and legendary timepieces. Our world-premiere materials confirm that Omega continues to be driven by its pioneering spirit.